Method and apparatus for making precision metal castings

Abstract

Metal to be cast is melted in melting chamber of casting furnace. Molten metal flows through a nozzle of the melting chamber is atomized by a stream of heated compressed air. Droplets of molten metal are carried by the air stream to a mold onto which the metal is cast to form a thin even molding. The hot air stream prevents the molten metal droplets from solidifying until they reach the mold. The amount of metal cast and the thickness of the molding may be controlled by adjusting the velocity of the air stream and the distance from the nozzle to the mold.

I claim: 
     
       1. A furnace for melting metal and casting the molten metal to form metal moldings, comprising: (a) a melting chamber for melting the metal to be cast;   (b) means for heating the melting chamber comprising a heating element wound around the melting chamber;   (c) thermostat means for controlling operation of the heating element;   (d) a nozzle in fluid communication with an opening in said melting chamber, through which molten metal flows;   (e) air tube means wound around the melting chamber with the heating element;   (f) a source of compressed air in fluid communication with said air tube means;   (g) means for heating air in said air tube means, comprising said heating element;   (h) a sleeve surrounding said nozzle, in fluid communication with said air tube means; and   (i) an opening in said sleeve through which heated air from said air tube means is accelerated as it exits said sleeve, said opening being oriented so that air exiting and sleeve atomizes and carries molten metal from said nozzle.   
     
     
       2. A furnace according to claim 1, further comprising mounting means enabling the furnace to move into a position for casting in which molten metal flows through said nozzle. 
     
     
       3. A furnace according to claim 1, wherein the position of said sleeve is adjustable along the longitudinal axis of said nozzle. 
     
     
       4. A furnace according to claim 1, wherein said heating element comprises a resistance heating tube. 
     
     
       5. A furnace according to claim 1 wherein the length and diameter of said air tube are such that during passage through said air tube the air is heated to about the melting point of the metal. 
     
     
       6. A furnace according to claim 1, wherein said melting chamber, said heating element, and said air tube are thermally connected.